Detergent and anti-oxidant lubricant



DETERGENT AND The present invention relates to a mineral oil composition and more particularly to the use of a novel additive to impart antioxidant and detergent properties to lubricating oils.

Various detergent additives have heretofore been proposed for use in mineral oil compositions, such as heavy duty lubricating oils, which are suitable for use as crankcase lubricants for internal combustion engines, including automobile, diesel and marine engines, which operate for long periods of time at high temperatures and in which the lubricant comes in contact with metal'surfaces. In general, the function of these detergent additives, such as, for example, the alkaline-earth metal salts of petroleum sulfonic acids, is to impart properties to the motor oil which will enable it to keep the pistons, rings and valves free of varnish and lacquer deposits by keeping oil oxidation products and other types of insoluble matter in suspension or dispersion so that these materials will not settleoutand adhere to metal surfaces. The oil-soluble metal salts of the petroleum sulfonic acids are among the most widely used additive agents to improve the detergent properties of lubricating oils. However, while these detergent additives perform satisfactorily in dispersing sludge and preventing lacquer deposits, many of these additives, particularly under extreme operating conditions, increase the rated oxidation of the oil and their presence effects an increase in the concentration of acidic oxidation products and thus an increased rate of corrosion to the bearings, pistons, valves and, the like.

In accordance with my invention, I have discovered a United States Patent C) furized sperm oil and the like.

new and useful detergent-antioxidant additive prepared by reacting basic barium petroleum sulfonate with a phosphorus sulfide-hydrocarbon reaction product. I have found that'this combination of constituents produces a detergent material having particularly desirable properties for use in lubricating oils, including sludge dispersant properties, anti-wear properties and the prevention of varnish formation and lacquer-like deposits. The useful additives of my invention provide lubricating oil compositions with improved resistance to oxidative deterioration whereby corrosion to valves, bearings, pistons and the like, is reduced ratherthan accelerated.

The novel detergent-antioxidant lubricating oil additives of this invention can be employed in amounts varying over a considerable range depending upon the intended purpose of the resultant composition and the conditions under which it is to be useds In compositions intended for use as crankcase lubricants for internal combustionengines, the proportion of additive based on the total weight of the mineral oil composition, may range from 0.01 to 20.0 weight percent, preferably is-from about 0.5 to .10.0 weight percent. In addition, the lubricant composition advantageously may contain from about 01.001 to 5 weight percent of anti-wear agentsand anti-oxidants such as elemental sulfur, zinc dithiophosphate, or otherorganic sulfur'compounds, such as sul- ICE Furthermore, the lubricant may contain other agents such as dyes, pour depressors, thickeners, viscosity index improvers and any of agents conventionally used as additives for lubricating oils.

In carrying out the preparation of the additives of this invention it is preferred to use chemically equivalent quantities of the reactants so as to obtain a neutral product. However, if a basic oil blend is desired than less than the chemical equivalent amount-of the phosphorus sulfide-hydrocarbon material should be used, preferably not less than about 50 percent of the equivalent amount, to obtain the reaction product and unreacted basic barium sulfonate.

The reaction between the basic barium sulfonate and the phosphorus sulfide-hydrocarbon material is carried out by mixing the materials at a temperature of from about room temperature to 500 F. or more, preferably about to 200 F. until the reaction is complete. Ordinarily, after about one hour the reaction is considered complete, although at lower temperatures, e.'g. to F., the product is thereafter heated to about 250 to 300 F. to remove the water of reaction. Although my new additive is described as a reaction product, I do not wish to be bound by this theory as there may in fact not be a reaction effected.

The basic organic sulfonates employed in the preparation of the lubricating compositions of my invention are the barium salts derived from the oil-soluble sulfonic acids produced in the treatmentof petroleum hydrocaI-.

bons with a sulfonatingagent such as sulfuric acid or sulfur trioxide. The preferentially oil-soluble sulfonic acids, generally referred to as mahogany acids, are conveniently employed as a concentrate in the oil from which they are derived and may be prepared by 'sulfonating a suitable petroleum distillate with fuming sulfuric acid'to obtain approximately a 10 weight percent concentration of mahogany acid in the acid oil, or by sulfonating with sulfur trioxide, in which case approximately a 20 weight percent concentration is obtained. The useful mahogany acids, which generally have a molecular weight of about 300 to 500 or higher, normally show a titratable acidity and may be converted into the basic barium salts by neutralization of the acid oil with an excess of basic metal compound to obtain a basic barium sulfonate of higher metal content than the normal'salt. In the preparation of the basic petroleum sulfonates, the amount of barium metal in excess of that theoretically required to replace Although the mahoganyacids contain a sulfonate conare employed in the present invention to produce the novel I Y lubricating; oil additives are the reaction products of a centration of about 10%, introduction of barium (3.5%)

gives abarium sulfonate concentration of about 137 i The phosphorus sulfide-hydrocarbon materials which sulfide of phosphorus with a suitable hydrocarbon material of lubricating viscosity such as a material of natural petroleum origin, for example, a heavy hydrocarbon oil of lubricating viscosity having a molecular weight above 500, i.e., residual lubricating oils, or a synthetic hydrocarbon material such as an olefin or olefin polymer having a molecular weight of from about 400 to 2000 or more. The sulfide of phosphorus which may be employed with the hydrocarbon material is preferably phosphorus pentasulfide, P 8 although P 8 P 8 or other phosphorus sulfides or mixtures thereof can be used. Ordinarily, the phosphorus sulfide-hydrocarbon reaction is carried out at a temperature of from about 200 to 500 F., preferably about 400 to 500 F., and in a nonoxidizing atmosphere, such as an atmosphere of nitrogen. The amount of phosphorus sulfide which can be used may range from 1 percent to 50 weight percent and is preferably from about 5 percent to 25 percent of the hydrocarbon material. The final reaction product will usually contain from about 1 to 6% by weight of organically combined phosphorus. v

In a preferred embodiment, a hydrocarbon material such as a mineral oil bright stock or cylinder stock having a viscosity within a range of about 120 to 300 SUS at 210 F. is reacted with 7 to 17 weight percent of phosphorus penta-sulfide at a temperature between about 400 to 500 F. for a period of about to 20 hours. By reacting a phosphorus sulfide with a bright stock for example, the formation of-oil-insoluble products which are pro-sludging in typical lubricating oil blends are greatly reduced as compared to the reaction with a lighter oil, such as a neutral oil, which affords a larger percentage of insoluble reaction products. Ordinarily, if the reaction mixture contains insoluble products these materials can be removed by filtration or centrifugation performed at an elevated temperature, usually about 150 to 280 F. Other suitable hydrocarbon oils which can be. reacted with phosphorus sulfide include olefins such as cetene, melene, high molecular Weight alkenes obtained by cracking petroleum oils, etc. and olefin polymers such as those obtainedfrom the liquid phase polymerization of butylene and isobutylene in the presence of a Friedel- Crafts type catalyst.

The base mineral lubricating composition will ordinarily depend upon the purpose for which the composition is intended and its service application. When the compounded oil is' to be used for the lubrication and protection of internal combustion engines, it is preferred to usea blend of conventionally finished Mid-Continent neutrals and Mid-Continent bright stocks. Other lubricating oil iractions or blends may be used to meet special lubricating requirements.

The method of preparing the additives of the present invention and their use in lubricating oils are illustrated in the following examples. These examples are given forillustrative purposes only and are not to be considered.

as limiting the scope of the invention. I The following example illustrates the preparation of basic barium sulfonate. I

' EXAMPLE 1 A sweet West. Texas gas oil fraction having a viscosity of 270SUS at 100 F.was treatedwith'fou'r 28pounds per barrel dumps of 20% oleuml After each 'dump of oleum the sludge was removed. After all of the oleum was added the acidetreatedoiliwas' blown with air to remove SO The acid-treated oil contained approximately 10% mahogany sulfonic acid and had an acid number of 14.1. Thereafterthe acid oil was'neutralized with ap proximately 0% theoretical-barium .oxidefin a water r oil used in the preparation of the 'and heated to 275 F.

, Percent barium 4 solution for several hours at 160 to 180 F. followed by dehydration by raising the temperature to 300 F. The product was filtered with Super-Cel to leave a basic barium sulfonate which analyzed as follows:

Percent barium 3.36 Base number to pH 4 13.9

llie percent barium for the normal salt is 1.7.

The method of preparing the phosphorus sulfide-hydrocarbon reaction product is described in Examples II and Ill.-

EXAMPLE 11 Percent sulfur 5.78 Percent phosphorus 3.13

Acid number 32.7

I EXAMPLE III 8500 pounds of Pennsylvania bright stock, viscosity SUS at 210 F., were charged to the reaction kettle 1500 pounds of P 8 were added with stirring and the temperature was maintained at 440 F. for 14 hours. The reaction mixture was cooled to 275 F. and filtered with Super-Col to give a product which analyzed as follows:

Percent sulfur 7.36

Percent phosphorus 4.11 Acid number 42.3

"The following examples illustrate the method of preparing my new additive by reacting basic barium sul fonate .with .a phosphorus sulfide-hydrocarbon reaction product.

In Example VI theamount of P S -l1ydrocarbon reaction product employed was. that calculated to neutralize the basic barium sulfonate. The product thus obtained is substantially neutrall; Example V was prepared by using less than the equivalent amount of P S -hydrocarbon material so as to obtain abasic product.

EXAMPLE 1v until the reaction was complete.

tion. The product analyzed as follows:

i p 2.46 Percent phosphor-us 0.82 Percent sulfur 1.98

Base number to p114}, 0.00

. EXAMPLE v 3 6810; grams of basic barium sulfonateconcentrate, as l prepared in-Examplel but containing 3.58% barium and having a base number to p114 of 13.6, were mixed with 563 grams of Pis -hydrocarbon reaction product as prepared in Example III. The mixture was heated to to F. for; one-half houriand then-heated to 250 F. to

The eifectiveness of the barium-P S -bright stock reaction product in imparting anti-Wear properties to lubrieating oils is demonstrated by the LS5 valve train wear test. The LS-S engine test is run in a 1953 Chevrolet Powerglide engine with 235 cubic inch displacement. The hydraulic valve lifters are made of chilled cast iron, the camshaft of forged steel and the rocker arms of malleable iron. The test duration is 24 hours at an engine speed of 3150 rpm. and with a load of 30 brake horsepower. The oil sump temperature is maintained at 255 F. and the valve springs are loaded to 150% of the normal static load. In this test the faces of the 12 hydraulic valve lifters tend to spall or pit if the oil is deficient in this particular type of anti-wear property.

Reaction products of either hydrocarbon-BS or steamed hydrocarbon-P 8 with basic barium sulfonate were blended to the same barium content (0.9%) as the reference oil. The reference oil used was an SAE 10W oil containing basic barium sulfonate, a zinc dialkyl dithiophosphate, viscosity index improver and foam inhibitor. It analyzed 0.9% barium and 0.09% phosphorus. Except for the replacement of the basic barium sulfonate with the specified new reaction products, the blends were identical with the reference oils. The following table shows the improved anti wear properties resulting from the use of the new reaction products.

Table I LS-5 ENGINE TEST RESULTS Additive Concentrate as Prepared inv Ex. No.-

Amount of Additive Concentrate, Wt.

percent 7 No. of Spalled Valve Lifters Additive Basic Barium Sulfonate of Reference Oil I Reaction Product V Table [I Additive Amount of Ooncen- Additive Rate of Oxygen Additive trate as Ooncen- Absorption Per Prepared trate, Wt. g. of Blend in Ex. percent in N0. BaseOil Basic Barium Suli0nate I 15.5 2,200 co. in 56 minutes. Basic Barium Sulfonate- Oil-P28 Reaction Product IV 21.1 1,656 cc. in 300 minutes.

I claim:

1. A lubricating oil composition consisting essentially of a mineral lubricating oil and from 0.01 to 20.0 weight percent of a product obtained by (l) contacting at a temperature of from about room temperature to 500 F. an oil-soluble basic barium petroleum sulfonate with not less than about 50 percent of the equivalent amount of an oil-soluble phosphorus sulfide-mineral oil bright stock reaction product, said bright stock being of lubricating viscosity and having a molecular weight above 500, and (2) removing water from the product, said water resulting from said contacting.

2. The composition of claim 1 wherein said lubricating composition contains 0.5 to 10.0 weight percent of said contacting product. v

3. The. composition of claim -1 wherein a chemically equivalent quantity of said phosphorus sulfide'bright stock reaction product is contacted with said sulfonate so as to obtain a su-bstantially neutral product.

4. The composition of claim 1 wherein said phosphorus sulfide bright stock product is prepared by reacting 7 to 17 weight percent of phosphorus pentasulfide with a mineral oil bright stock having a viscosity within the range of about to 300 SUS at 210 F. at a temperature be References Cited in the file of this patent UNITED STATES PATENTS 2,419,584 Noland Q Apr. 29, 1947 2,421,004 Berger et al. May 27, 1947 2,476,813 Buckmann et al. July .19, 1949 2,476,972 Fuller et al. July 26, 1949 2,493,216 Berger et al. f Ian. 3, 1950 7 2,538,696 May Jan. 16, 1951 2,546,552 Loane et al Mar. 27, 1951 2,623,016 Mertes Dec. 23, 1952 2,681,891 Bos et al June 22, 1954 2,723,236 Asseif et al. Nov. 8, 1955 2,767,164 Assetf et al. Oct. 16, 1956 2,798,045 Buck et al. July 2, 1957 2,969,324

Knapp et al J an. 24,1961 

1. A LUBRICATING OIL COMPOSITION CONSISTING ESSENTIALLY OF A MINERAL LUBRICATING OIL AND FROM 0.01 TO 20.0 WEIGHT PERCENT OF A PRODUCT OBTAINED BY (1) CONTACTING AT A TEMPERATURE OF FROM ABOUT ROOM TEMPERATURE TO 500*F. AN OIL-SOLUBLE BASIC BARIUM PETROLEUM SULFONATE WITH NOT LESS THAN ABOUT 50 PERCENT OF THE EQUIVALENT AMOUNT OF AN OIL-SOLUBLE PHOSPHORUS, SULFIDE-MINERAL OIL BRIGHT STOCK REACTION PRODUCT, SAID BRIGHT STOCK BEING OF LUBRICATING VISCOSITY AND HAVING A MOLECULAR WEIGHT ABOVE 500, AND (2) REMOVING WATER FROM THE PRODUCT, SAID WATER RESULTING FROM SAID CONTACTING. 